refactor changes

src/api/fonts.ts

@@ -0,0 +1,14 @@
+// The machine's font book, for the half of the font picker this app does not ship.
+
+import { call } from "../ipc";
+
+/**
+ * Every family installed on this machine, sorted and deduplicated by the backend.
+ *
+ * Answers with an empty list rather than rejecting when there is no backend to ask, because the
+ * picker's bundled half works perfectly well without this one and an empty "System" group is the
+ * honest way to say the machine was not asked. The list is worth caching in the caller: it walks
+ * several directories on the Rust side and cannot change while the app is running.
+ */
+export const fontsListSystem = (): Promise<string[]> =>
+  call<string[]>("fonts_list_system").catch(() => []);